!! File: WaveSums.68k
!! Sept 13, 2003, Hubert Hohn for Haynes Miller, MIT

PUBLIC PCFlag,Mac5Flag,M68KFlag,UnixFlag,xmax,ymax
PUBLIC toolLft,toolRgt,toolBas,toolTop,toolhdr,toolHgt,toolWid  ! tool boundaries
PUBLIC winLft,winRgt,winBas,winTop,winHgt,winWid      ! window
PUBLIC workLft,workRgt,workBas,workTop,workMidx  ! work area
PUBLIC backclr,black,drkgry,drkmid,midgry,litmid,litgry,white
PUBLIC red,yellow,green,cyan,blue,magenta,pink,colorscheme
PUBLIC planeclr,gridclr,rimclr,axisclr,axislabelclr,titleclr,rightsclr
PUBLIC numberlineclr,slotdrkclr,slotlgtclr,slideclr
PUBLIC largefonts, title$, SLUmode

LET toolHgt= 560
LET toolWid= 780
LET window$= "The d'Arbeloff Interactive Math Project"
LET colorscheme= 0

LET title$ = "Wave Sums"

SUB ThisProgram
    CALL WaveSums
    CLEAR
END SUB


!! ---------------------------------------------------------
!! ------ Start TB4 Mac Header and Subs ------

!LET M68KFlag = 1
!LIBRARY "MacTools*", "HHLib.trc"
!ASK PIXELS winWid,winHgt
!LET winLft= 0
!LET winTop= 0
!LET winRgt= winWid-1
!LET winBas= winHgt-1
!SET WINDOW 0,winRgt,winBas,0
!CALL Palette
!CLEAR
!
!CALL ToolPanel
!CALL ThisProgram
!
!END
!EXTERNAL
!
!MODULE Mac4Parts
!    SUB SetTextFont(font,size,style$)
!        CALL MacTextFont(font)
!        CALL MacTextSize(size)
!        CALL MacTextFace(style$)
!    END SUB
!
!    SUB StringWidth(sw$,sl)
!        DECLARE DEF MacStringWidth
!        LET sl= MacStringWidth(sw$)
!    END SUB
!
!    SUB SetLineWeight(wgt)
!        CALL MacPenSize(wgt,wgt)
!    END SUB
!
!    SUB BoxDisk(Lft,Rgt,Bas,Top)
!        CALL MacPaintOval(Lft,Rgt,Bas,Top)
!    END SUB
!END MODULE

!! --- End TB4 Mac Header and Subs ---
!!---------------------------------------------------------
!!--- Start TB5 Cross-Platform header and subs ---

LIBRARY "c:\TB Gold\TBLibs\TrueCtrl.trc"     ! windows
LIBRARY "c:\TB Gold\TBLibs\HHLib.trc"

!LIBRARY ":TBLibs:TrueCtrl.trc"                   ! macintosh
!LIBRARY "HHLib.trc"
!
PUBLIC WinID
DECLARE PUBLIC OBJM_SET,OBJM_SYSINFO
LET winHgt= toolHgt
LET winWid= toolWid
DIM values(1)

CALL TC_Init

CALL Object(OBJM_SYSINFO,WinID,"MACHINE",system$,values())
IF system$="MAC" then
   LET Mac5Flag= 1
ELSE IF system$="WIN32" then
   LET PCFlag  = 1
END IF

CALL TC_SetUnitsToPixels                         ! 5.1 and up needs this
CALL TC_GetScreenSize(scrnLft,scrnRgt,scrnBas,scrnTop)
LET winLft= int((scrnRgt-scrnLft-winWid)/2)
LET winRgt= winLft+winWid-1
LET winTop= int((scrnBas-scrnTop-winHgt)/2) + 10
LET winBas= winTop+winHgt-1

CALL TC_Win_Create (WinID,"TITLE",winLft,winRgt,winBas,winTop)
LET values(1)= 2
CALL Object(OBJM_SET, WinID, "TYPE", "", values())

IF PCFlag=1 then                                 ! kill dithering
   LET  values(1)= 1
   CALL Object(OBJM_SET, WinID, "SOLID MIX", "", values())
END IF

LET  values(1)= 0
CALL TC_SetRect(WinID,winLft,winRgt,winBas,winTop)
CALL TC_Win_SetTitle(WinID,window$)
CALL TC_Show(WinID)

SET MODE "COLORSTANDARD"

ASK PIXELS winWid,winHgt                         ! must follow set mode
LET winLft= 0
LET winTop= 0
LET winRgt= winWid-1
LET winBas= winHgt-1
SET WINDOW 0,winRgt,winBas,0

CALL Palette

IF PCFlag=1 then
   LET  values(1)= 0                             ! now force solid colors
   CALL Object(OBJM_SET, WinID, "SOLID MIX", "", values())
   CALL TC_Win_RealizePalette(WinID)             ! some PCs need this

   CALL TC_Win_SetFont(WinID,"arial",9,"plain")
   CALL StringWidth("0",sw)
   IF sw>7 then LET largefonts=1 else LET largefonts=0
END IF

CALL TC_Win_Switch(WinID)

CALL ToolPanel
CALL ThisProgram

CALL SetTextFont(1,12,"bold")                    ! now shut down and clean up
LET quit$= "click the mouse or press a key to close..."
CALL PlotTextCJ(workmidx,(workbas+worktop)/2,quit$,yellow)
CALL TC_CleanUp

END
EXTERNAL

MODULE TB5Parts
    SUB StringWidth(sw$,sl)
        DECLARE PUBLIC WinID
        LET sl= StrWidth(WinID,sw$)
    END SUB

    SUB SetLineWeight(wgt)
        DECLARE PUBLIC OBJM_SET
        DECLARE PUBLIC WinID
        DIM values(1)
        LET values(1)= wgt
        CALL Object(OBJM_SET,WinID, "WIDTH", "", values())
    END SUB

    SUB SetTextFont(font,size,style$)
        DECLARE PUBLIC WinID,Mac5Flag,PCFlag,largefonts
        IF Mac5Flag=1 then
           SELECT CASE font
           CASE 4
                LET font$= "Courier"
           CASE 16
                LET font$= "Times"
           CASE else
                LET font$= "Geneva"
           END SELECT
        ELSE IF PCFlag=1 then
           IF largefonts=1 then
              IF size<12 then
                 LET size=  6
              ELSE IF size=14 then
                 LET size= 10
              ELSE IF size=18 then
                 LET size= 12
              ELSE IF size=24 then
                 LET size= 14
              ELSE IF size=12 then
                 LET size=  8
              ELSE
                 LET size= round(72/96 * size * .8)
              END IF
           ELSE
              IF size<12 then
                 LET size=  7
              ELSE IF size=14 then
                 LET size= 12
              ELSE IF size=12 then
                 LET size=  9
              ELSE IF size=18 then
                 LET size= 14
              ELSE IF size=24 then
                 LET size= 18
              ELSE
                 LET size= round(72/96 * size)
              END IF
           END IF
           SELECT CASE font
           CASE 4
                LET font$= "Courier New"
           CASE 16
                LET font$= "Times New Roman"
           CASE else
                LET font$= "Verdana"
           END SELECT
        END IF
        IF style$= "normal" then LET style$= "plain"
        CALL TC_Win_SetFont(WinID,font$,size,style$)
    END SUB

    SUB BoxDisk(Lft,Rgt,Bas,Top)
        BOX DISK Lft,Rgt,Bas,Top
    END SUB
END MODULE

!  --- End TB5 Cross-platform header and subs ---
!! ---------------------------------------------------------

!! --- Start Unix Header and Subs ---

!LIBRARY "HHLib.trc"
!LET UnixFlag= 1
!ASK PIXELS winWid,winHgt
!LET winLft= 0
!LET winTop= 0
!LET winRgt= winWid-1
!LET winBas= winHgt-1
!SET WINDOW 0,winRgt,winBas,0
!CALL Palette
!
!CALL ToolPanel
!CALL ThisProgram
!
!END
!EXTERNAL
!
!MODULE UnixParts
!    SHARE CharWidth
!
!    SUB SetTextFont(font,size,style$)
!        LET font$= "-adobe-courier-"
!        IF style$= "normal" then
!           LET style$= "medium-r-normal--"
!        ELSE
!           LET style$= "bold-r-normal--"
!        END IF
!        IF size=9 then
!           LET size$= str$(10)
!        ELSE
!           LET size$= str$(size)
!        END IF
!        LET test= SetFont(font$&style$&size$&"*")
!
!        IF size=9 then
!           LET CharWidth=  7
!        ELSE IF size=12 then                     ! numeric output - axis labels
!           LET CharWidth=  8
!        ELSE IF size=14 then                     ! rare
!           LET CharWidth=  9
!        ELSE IF size=18 then                     ! rare
!           LET CharWidth= 10
!        END IF
!    END SUB
!
!    SUB StringWidth(sw$,sl)                      ! string width in pixels
!        ! LET sl= StrWidth(sw$)
!        LET chars= len(sw$)
!        LET sl   = chars*CharWidth
!    END SUB
!
!    SUB SetLineWeight(wgt)
!        ! CALL PenSize(wgt,wgt)
!    END SUB
!
!    SUB BoxDisk(Lft,Rgt,Bas,Top)
!        CALL Fill_Circle(Lft,Rgt,Bas,Top)
!    END SUB
!END MODULE

!! ------ End of TB Unix Header and Subs ------
! -----------------------------------------------------------


! ***

SUB WaveSums
    DECLARE PUBLIC black,drkgry,drkmid,midgry,litmid,litgry,white
    DECLARE PUBLIC red,yellow,green,cyan,blue,magenta,colorscheme
    DECLARE PUBLIC slideclr,axisclr,axislabelclr,true,false
    DECLARE PUBLIC workLft,workRgt,workBas,workTop,workMidx
    DECLARE DEF quitWithin,infoWithin

    ! --- help screen array ---

    DIM  info$(1:12)
    MAT READ info$

    DATA "Wave Sums"
    DATA ""
    DATA "This tool supports graphical exploration of the sum of two moving waves. The red wave moves to the right, the green wave moves to the left, and their sum is displayed in yellow."
    DATA ""
    DATA "The waves can be toggled on and off by clicking the check boxes for Left, Right, and Sum."
    DATA "Roll the mouse over the xt plane to display a vertical rule and its position as an angle in degrees."
    DATA ""
    DATA "Click the [v] popdown menu button to display the wave sum equations. Click one of the equations to select it."
    DATA ""
    DATA "Click or drag the t slider handle to set the time variable, and display the wave graphs for that time."
    DATA "Click the [<][>] step buttons to change t by .05. Click the [>>>] animation button to animate the motion."
    DATA "Click among the slider hash marks to jump to the nearest quarter pi."


    ! --- colors ---

    LET lftclr= green
    LET rgtclr= red
    LET sumclr= yellow

    ! ---------- Utility functions ---

    DECLARE DEF clamp,roundn,e

    ! --- functions - not used - replaced by vector list ---

    DECLARE DEF asin

    DEF ZigZag(x)
        LET n= sin(x)
        IF abs(n)<1 then
           LET ZigZag=  atn(n/sqr(1-n*n))
        ELSEIF n=1 then
           LET ZigZag=  pi2
        ELSEIF n=-1 then
           LET ZigZag= -pi2
        END IF
    END DEF

    LET eq= 2

    DEF f(x,t)                                   ! wave from left
        IF eq=1 then
           LET f= sin(x+t)
        ELSE IF eq=2 then
           LET f= sin(x+t)
        ELSE IF eq=3 then
           LET f= ZigZag(x+t)
        END IF
    END DEF

    DEF g(x,t)                                   ! wave from right
        IF eq=1 then
           LET g= sin(x-t)
        ELSE IF eq=2 then
           LET g= sin(2*x-t)
        ELSE IF eq=3 then
           LET g= ZigZag(x-t)
        END IF
    END DEF

    SUB Constants                                ! used to define vertices
        LET x1  = -pi
        LET y1  =  0
        LET x8  =  2*pi
        LET y8  =  0
        LET t2  =  t*2
        LET pi2 =  pi*2
        LET pid2=  pi/2
        LET pi3 =  pi*3
        LET x23 = -pi/2
        LET x45 =  pi/2
        LET x67 =  3*pi/2
        LET w1RollStep = pi/360
    END SUB


    ! ----- design and layout - sizes and positions of interface -----

    ! ------------ Graphing plane parameters and methods -------------

    ! ------ plane 1 data ------

    DECLARE PUBLIC w1Lft,w1Rgt,w1Bas,w1Top,w1Midx,w1Midy
    DECLARE PUBLIC w1fLft,w1fRgt,w1fBas,w1fTop,w1x0,w1y0
    DECLARE PUBLIC w1xFirst, w1xSTik, w1xLTik, w1xLabel, w1xGridstep
    DECLARE PUBLIC w1yFirst, w1ySTik, w1yLTik, w1yLabel, w1yGridstep
    DECLARE PUBLIC w1wWid,w1wHgt,w1fWid,w1fHgt
    DECLARE PUBLIC w1fxRatio,w1fyRatio,w1wxRatio,w1wyRatio,w1Aspect
    DECLARE PUBLIC w1xPiFlag, w1xMult, w1yPiFlag, w1yMult

    LET w1Flag   = 1
    LET w1xPiFlag= 1
    LET w1xMult  = pi
    LET w1yPiFlag= 0
    LET w1yMult  = 1

    LET w1Lft = workLft  + 80                    ! pixel bounds
    LET w1Rgt = w1Lft + 600
    LET w1Top = workTop + 50
    LET w1Bas = w1Top + 320

    LET w1fLft= -1                               ! function bounds
    LET w1fRgt=  2
    LET w1fTop=  4
    LET w1fBas= -4

    LET w1xAx$= "t"                              ! axis labels
    LET w1yAx$= "x"

    LET w1xGridstep= 0                           ! horizontal grid intervals
    LET w1yGridstep= 0                           ! vertical grid intervals

    LET w1xSTik = 1/4                            ! horizontal axis Tik marks
    LET w1xLTik = 1/2
    LET w1xLabel= 1
    LET w1xFirst= w1fLft

    LET w1ySTik = 0                              ! vertical axis Tik marks
    LET w1yLTik = 1
    LET w1yLabel= 1
    LET w1yFirst= w1fBas

    ! ------ Plane 1 methods ------

    DECLARE DEF w1fncx,w1fncy,w1wndx,w1wndy      ! window/function transforms
    DECLARE DEF w1wWithin, w1Within

    CALL w1Variables

    DIM lftlist(0:1,0:1),rgtlist(0:1,0:1),sumlist(0:1,0:1)
    MAT redim lftlist(0:w1wWid,0:1),rgtlist(0:w1wWid,0:1),sumlist(0:w1wWid,0:1)

    SUB w1Init
        CALL w1DrawPlane(1,1,1)                  ! x axis, y axis, zeroaxes
        LET wx= w1Wndx(pi)
        CALL PlotLine( wx,w1Top+1, wx,w1Bas-1, drkmid)
        CALL SetTextFont(1,12,"bold")
        CALL PlotTextLJ(w1Rgt+8,w1y0+3,w1xAx$,axislabelclr)     ! axis labels
        CALL PlotTextCJ(w1x0,w1Top-10,w1yAx$,axislabelclr)
        CALL w1KeepGridLayer
    END SUB

    ! ----------- horizontal sliders ------------

    ! --- h1 horizontal slider ---

    ! --- h1 data ---

    DECLARE PUBLIC h1axis,h1wLft,h1wRgt,h1wBas,h1wTop,h1fLft,h1fRgt
    DECLARE PUBLIC h1name$,h1form$,h1clr,h1First,h1STik,h1LTik,h1Label
    DECLARE PUBLIC h1PiAxis,h1Mult,h1fMin,h1fMax

    LET h1PiAxis= 1
    LET h1Mult  = pi

    LET h1clr   = white
    LET h1name$ = "t"
    LET h1form$ = "--%.##"
    LET h1Places= 2

    LET h1axis  = w1Bas  +  24
    LET h1wLft  = w1Rgt  - 400
    LET h1wRgt  = h1wLft + 400

    LET h1fLft  = 0
    LET h1fRgt  = 2

    LET h1STik  = 0.25                           ! short tick marks
    LET h1LTik  = 0.50                           ! long tick marks
    LET h1Label = 0                              ! labels
    LET h1First = 0                              ! first tick mark
    LET h1Click = 0.25*pi                        ! tik mark click step

    LET h1AnimStep= .05                          !pi/90                        ! animation step
    LET h1fMin    = 0
    LET h1fMax    = h1fRgt*h1Mult

    ! --- h1 methods ---

    DECLARE DEF h1Wndx,h1Within                  ! window/function transforms
    DECLARE DEF h1AnimWithin,h1AnimStopWithin
    DECLARE DEF h1LstpWithin,h1RstpWithin

    CALL h1SliderVariables

    SUB h1Init(t)
        CALL h1DrawSlider(h1name$,t)
        CALL h1AnimButtons
    END SUB


    ! ------- text boxes - t rollover --------

    LET t1BasLn= w1Top-25
    LET t1Top  = t1BasLn-15
    LET t1Bas  = t1BasLn+ 5
    LET t1Lft  = w1Lft-30
    LET t1Rgt  = w1Rgt+30
    LET t1Form$= "---%"

    SUB t1ValueSet(x)
        LET deg= 180*x/pi
        LET wx = w1Wndx(x)
        CALL t1ValueClear
        CALL PlotDegreesCJ(wx,t1BasLn,deg,litgry)
    END SUB

    SUB t1ValueClear
        BOX CLEAR w1Lft-30,w1Rgt+30,w1Top-20,w1Top-40
    END SUB


    ! --- check boxes - graph switches ---

    DECLARE PUBLIC c1cnt, c1stp, c1siz
    DECLARE PUBLIC c1lft, c1rgt, c1bas, c1top
    DECLARE PUBLIC c1NameList$(),c1ColorList(),c1Switch()
    DECLARE DEF c1Within

    LET c1cnt= 3                                 ! box count
    LET c1top= h1wBas+40
    LET c1lft= w1Lft

    CALL c1Variables

    MAT redim c1NameList$(1:c1cnt)
    DATA "Right","Left","Sum"
    MAT READ c1NameList$

    MAT redim c1ColorList(1:c1cnt)
    DATA 23,25,24                                ! 7, 9, 8
    MAT READ c1ColorList

    MAT redim c1Switch(1:c1cnt)
    DATA 0, 0, 1
    MAT READ c1Switch

    SUB c1Init
        CALL c1DrawCheckBoxes
        CALL c1SetCheckBox
    END SUB

    ! ----- popup menu parameters -----

    DECLARE PUBLIC m1Lft, m1Rgt, m1Bas, m1Top, m1Equation, m1Prefix$, m1Menu1$(), m1tClr
    DECLARE DEF m1Within

    MAT redim m1Menu1$(1:3)
    MAT READ m1Menu1$
    DATA "sin(x+t) + sin(x-t)"
    DATA "sin(x+t) + sin(2x-t)"
    DATA "zig zag"

    LET m1Prefix$ = "y = "
    LET m1Lft     = h1wLft
    LET m1Top     = h1wBas+40
    LET m1tClr    = yellow
    LET m1Equation= 1


    ! ----- end of design and layout definitions -----




    ! --- default parameters ---

    LET t= pi/4
    CALL Constants
    LET eq,m1Equation= 2

    ! --- Draw the screen ---

    CALL InitScreen
    CALL SetTimer                                ! tune timer to cpu
    CALL m1InitMenu1

    SUB InitScreen
        BOX CLEAR worklft,workrgt,workbas,worktop

        CALL h1Init(t)                           ! slider
        CALL w1Init                              ! graph plane
        CALL c1Init                              ! check boxes

        IF eq=3 then
           CALL Graph(t)
        ELSE
           CALL SineGraphs(t)
        END IF

        CALL m1ResetMenu(menuState)

        ! CALL m1Init
    END SUB


    ! --------------- Main Event Manager Loop ---------------

    DO
       LET clearflag= 0

       IF ms<>2 then                             ! if mouse not down
          DO
             GET MOUSE: mx,my,ms
             CALL w1RollOver(mx)
          LOOP until ms=2                        ! mouse state - down?
       END IF
       IF clearflag=1 then
          CALL w1RollOverClear
       END IF

       IF h1Within(mx,my)=true then
          IF my<h1axis then
             CALL h1MouseClick(ms)
          ELSE
             CALL h1MouseDrag(ms)
          END IF

       ELSE IF h1animWithin(mx,my)=true then     ! animate
          CALL h1AnimButtonUp(ms)
          CALL Animate
       ELSE IF h1LstpWithin(mx,my)=true then     ! left step
          CALL h1LstpButtonUp(ms)
          CALL h1LeftStep(t,h1AnimStep)
          CALL h1Action
       ELSE IF h1RstpWithin(mx,my)=true then     ! right step
          CALL h1RstpButtonUp(ms)
          CALL h1RightStep(t,h1AnimStep)
          CALL h1Action

       ELSE IF c1Within(mx,my)=true then
          CALL MouseUp(mx,my,ms)
          LET ChkBox= int((my-c1top)/c1stp) + 1  ! which check box
          LET c1Switch(ChkBox)= 1-c1Switch(ChkBox)    ! binary switch
          CALL c1SetCheckBox
          IF eq=3 then
             CALL Graph(t)
          ELSE
             CALL SineGraphs(t)
          END IF

       ELSE IF m1Within(mx,my)=true then
          CALL MouseButtonUp(m1Lft,m1Rgt,m1Bas,m1Top,ms)
          CALL m1ReadMenu
          LET eq= m1Equation
          IF eq=3 then
             CALL Graph(t)
          ELSE
             CALL SineGraphs(t)
          END IF

       ELSE IF infoWithin(mx,my,ms)=true then
          CALL infoButtonUp(ms)
          CALL InfoPage(Info$)
          CALL InitScreen
       ELSE IF quitWithin(mx,my,ms)=true then
          CALL quitButtonUp(ms)
          EXIT SUB
       ELSE
          CALL MouseUp(mx,my,ms)
       END IF
    LOOP

    ! --- w1 rollover event ---

    SUB w1RollOver(mx)
        IF w1Within(mx,my)=1 then
           LET mx= clamp(mx,w1Lft,w1Rgt)
           IF mx<>oldmx then
              LET x= w1Fncx(mx)
              LET x= roundn(x,w1RollStep)        ! step one degree

              CALL w1ShowGraphLayer              ! show graph layer
              CALL PlotLine( mx,w1Top+1, mx,w1Bas-1, litgry)    ! vertical rule
              CALL t1ValueSet(x)

              LET clearflag= 1
              LET oldmx    = mx
           END IF
        ELSE IF clearflag=1 then
           CALL w1RollOverClear
        END IF
    END SUB

    SUB w1RollOverClear
        CALL w1ShowGraphLayer                    ! show graph layer
        CALL t1ValueClear
        LET clearflag= 0
    END SUB

    ! --- h1 slider event ---

    SUB h1MouseClick(ms)
        CALL h1GetClickVal(ms,h1Click,t)
        CALL h1Action
    END SUB
    SUB h1MouseDrag(ms)
        DO
           CALL h1GetDragVal(ms,h1Places,t)
           CALL h1Action
        LOOP until ms=3
    END SUB

    SUB h1Action
        IF t<>oldt then
           IF eq=3 then
              CALL Graph(t)
           ELSE
              CALL SineGraphs(t)
           END IF
           LET oldt= t
        END IF
    END SUB

    ! --- h1 button event ---

    SUB Animate
        DO
           LET t= t + h1AnimStep
           LET t= mod(t,pi2)
           IF eq=3 then
              CALL Graph(t)
           ELSE
              CALL AnimateSineGraphs(t)
           END IF
           CALL h1Mark(t)

           GET MOUSE: mx,my,ms
           IF ms=2 then                          ! mouse down?
              CALL h1AnimStopButtonUp(ms)
              EXIT DO
           END IF
           CALL Delay(1/16)                      ! speed control
        LOOP
        CALL w1KeepGraphLayer
    END SUB


    ! --- Tool specific drawing and typesetting routines ---

    SUB SineGraphs(t)
        CALL w1ShowGridLayer
        IF c1Switch(1)=true then
           SET COLOR red
           FOR wx= w1Lft to w1Rgt step 2
               LET x= w1Fncx(wx)
               LET y= f(x,t)
               PLOT wx,w1Wndy(y);
           NEXT wx
           PLOT
        END IF
        IF c1Switch(2)=true then
           SET COLOR green
           FOR wx= w1Lft to w1Rgt step 2
               LET x= w1Fncx(wx)
               LET y= g(x,t)
               PLOT wx,w1Wndy(y);
           NEXT wx
           PLOT
        END IF
        IF c1Switch(3)=true then
           SET COLOR yellow
           FOR wx= w1Lft to w1Rgt step 2
               LET x= w1Fncx(wx)
               LET y= f(x,t)+g(x,t)
               PLOT wx,w1Wndy(y);
           NEXT wx
           PLOT
        END IF
        CALL w1KeepGraphLayer
    END SUB

    SUB AnimateSineGraphs(t)
        CALL w1ShowGridLayer
        IF c1Switch(3)=true then
           SET COLOR yellow
           FOR wx= w1Lft to w1Rgt step 5
               LET x= w1Fncx(wx)
               LET y= f(x,t)+g(x,t)
               PLOT wx,w1Wndy(y);
           NEXT wx
           PLOT
        END IF
        IF c1Switch(1)=true then
           SET COLOR red
           FOR wx= w1Lft to w1Rgt step 5
               LET x= w1Fncx(wx)
               LET y= f(x,t)
               PLOT wx,w1Wndy(y);
           NEXT wx
           PLOT
        END IF
        IF c1Switch(2)=true then
           SET COLOR green
           FOR wx= w1Lft to w1Rgt step 5
               LET x= w1Fncx(wx)
               LET y= g(x,t)
               PLOT wx,w1Wndy(y);
           NEXT wx
           PLOT
        END IF
    END SUB

    SUB Graph(t)
        ! calculates vertices and connects them
        ! faster than using a function to plot every pixel

        LET tpi= t
        LET t2 = tpi*2

        IF tpi>=0 and tpi<pi/2 then              ! t is 0 to 90

           ! --- sum graph vertices

           LET tshift= tpi
           LET yshift= round(pi-t2,6)

           LET y23= -yshift
           LET x2 =  x23 - tshift
           LET y2 =  y23
           LET x3 =  x23 + tshift
           LET y3 =  y23

           LET y45=  yshift
           LET x4 =  x45 - tshift
           LET y4 =  y45
           LET x5 =  x45 + tshift
           LET y5 =  y45

           LET y67=  y23
           LET x6 =  x67 - tshift
           LET y6 =  y67
           LET x7 =  x67 + tshift
           LET y7 =  y67

           ! --- left moving graph vertices

           LET ly1= -tpi

           LET lx2=  x2
           LET ly2= -pid2
           LET lx3=  x4
           LET ly3=  pid2
           LET lx4=  x6
           LET ly4= -pid2

           LET ly5=  tpi

           ! --- right moving graph vertices

           LET ry1=  tpi

           LET rx2=  x3
           LET ry2= -pid2
           LET rx3=  x5
           LET ry3=  pid2
           LET rx4=  x7
           LET ry4= -pid2

           LET ry5= -tpi

        ELSE IF tpi>=pi/2 and tpi<pi then        ! t is 90 to 180

           ! --- sum graph vertices

           LET tshift= tpi - pi
           LET yshift= round(pi-t2,6)

           LET y23= -yshift
           LET x2 =  x23 + tshift
           LET y2 =  y23
           LET x3 =  x23 - tshift
           LET y3 =  y23

           LET y45=  yshift
           LET x4 =  x45 + tshift
           LET y4 =  y45
           LET x5 =  x45 - tshift
           LET y5 =  y45

           LET y67=  y23
           LET x6 =  x67 + tshift
           LET y6 =  y67
           LET x7 =  x67 - tshift
           LET y7 =  y67

           ! --- left moving graph vertices

           LET myshift= pi - tpi

           LET ly1= -myshift

           LET lx2=  x3
           LET ly2=  pid2
           LET lx3=  x5
           LET ly3=  -pid2
           LET lx4=  x7
           LET ly4=  pid2

           LET ly5=  myshift

           ! --- right moving graph vertices

           LET ry1= myshift

           LET rx2=  x2
           LET ry2=  pid2
           LET rx3=  x4
           LET ry3=  -pid2
           LET rx4=  x6
           LET ry4=  pid2

           LET ry5=  -myshift

        ELSE IF tpi>=pi and tpi<pi3/2 then       ! t is 180 to 270

           ! --- sum graph vertices

           LET tshift= tpi - pi
           LET yshift= round(pi3 - t2,6)

           LET y23=  yshift

           LET x2 =  x23  - tshift
           LET y2 =  y23
           LET x3 =  x23  + tshift
           LET y3 =  y23

           LET y45= -yshift

           LET x4 =  x45 - tshift
           LET y4 =  y45
           LET x5 =  x45 + tshift
           LET y5 =  y45

           LET y67=  y23

           LET x6 =  x67 - tshift
           LET y6 =  y67
           LET x7 =  x67 + tshift
           LET y7 =  y67

           ! --- left moving graph vertices

           LET myshift= tpi - pi

           LET ly1=  myshift

           LET lx2=  x2
           LET ly2=  pid2
           LET lx3=  x4
           LET ly3= -pid2
           LET lx4=  x6
           LET ly4=  pid2

           LET ly5= -myshift

           ! --- right moving graph vertices

           LET ry1= -myshift

           LET rx2=  x3
           LET ry2=  pid2
           LET rx3=  x5
           LET ry3= -pid2
           LET rx4=  x7
           LET ry4=  pid2

           LET ry5=  myshift

        ELSE IF tpi>=pi3/2 and tpi<=pi2 then     ! t is 270 to 360

           ! --- sum graph vertices

           LET tshift= tpi - pi2
           LET yshift= round(pi3 - t2,6)

           LET y23=  yshift

           LET x2 =  x23 + tshift
           LET y2 =  y23
           LET x3 =  x23 - tshift
           LET y3 =  y23

           LET y45= -yshift

           LET x4 =  x45 + tshift
           LET y4 =  y45
           LET x5 =  x45 - tshift
           LET y5 =  y45

           LET y67=  y23

           LET x6 =  x67 + tshift
           LET y6 =  y67
           LET x7 =  x67 - tshift
           LET y7 =  y67

           ! --- left moving graph vertices

           LET myshift= pi/2 - (tpi-3*pi/2)

           LET ly1= myshift

           LET lx2=  x3
           LET ly2= -pid2
           LET lx3=  x5
           LET ly3=  pid2
           LET lx4=  x7
           LET ly4= -pid2

           LET ly5= -myshift

           ! --- right moving graph vertices

           LET ry1= -myshift

           LET rx2=  x2
           LET ry2= -pid2
           LET rx3=  x4
           LET ry3=  pid2
           LET rx4=  x6
           LET ry4= -pid2

           LET ry5=  myshift
        END IF

        ! ----- convert math vars to pixels -----

        ! ----- sum graph

        LET wx1= w1Lft
        LET wy1= w1Wndy(0)

        CALL w1MathToPixels(x2,y2, wx2,wy2)
        CALL w1MathToPixels(x3,y3, wx3,wy3)
        CALL w1MathToPixels(x4,y4, wx4,wy4)
        CALL w1MathToPixels(x5,y5, wx5,wy5)
        CALL w1MathToPixels(x6,y6, wx6,wy6)
        CALL w1MathToPixels(x7,y7, wx7,wy7)

        LET wx8= w1Rgt
        LET wy8= w1Wndy(0)

        ! ----- left moving graph

        LET lwx1= w1Lft
        LET lwy1= w1Wndy(ly1)

        CALL w1MathToPixels(lx2,ly2, lwx2,lwy2)
        CALL w1MathToPixels(lx3,ly3, lwx3,lwy3)
        CALL w1MathToPixels(lx4,ly4, lwx4,lwy4)

        LET lwx5= w1Rgt
        LET lwy5= w1Wndy(ly5)

        ! ----- right moving graph

        LET rwx1= w1Lft
        LET rwy1= w1Wndy(ry1)

        CALL w1MathToPixels(rx2,ry2, rwx2,rwy2)
        CALL w1MathToPixels(rx3,ry3, rwx3,rwy3)
        CALL w1MathToPixels(rx4,ry4, rwx4,rwy4)

        LET rwx5= w1Rgt
        LET rwy5= w1Wndy(ry5)

        ! ----- draw zigzags that are on -----

        CALL w1ShowGridLayer                     ! show grid buffer  

        IF c1Switch(1)=true then                 ! right moving graph
           SET COLOR rgtclr
           PLOT rwx1,rwy1; rwx2,rwy2; rwx3,rwy3; rwx4,rwy4; rwx5,rwy5
        END IF
        IF c1Switch(2)=true then                 ! left moving graph
           SET COLOR lftclr
           PLOT lwx1,lwy1; lwx2,lwy2; lwx3,lwy3; lwx4,lwy4; lwx5,lwy5
        END IF
        IF c1Switch(3)=true then                 ! sum graph
           SET COLOR sumclr
           PLOT wx1,wy1; wx2,wy2; wx3,wy3; wx4,wy4; wx5,wy5; wx6,wy6; wx7,wy7; wx8,wy8
        END IF

        CALL w1KeepGraphLayer                    ! buffer for rollover
    END SUB
END SUB

! --- end of zigzag code -------------------